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Topic: Speaker Power Vs. SPL |
Kevin Raymer
From:
Chalybeate, Kentucky, USA
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Posted 13 Oct 2014 1:30 pm |
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I don't think I've ever done the math on this, actually I know I havn't.
Will two 25 watt speakers driven by a 50 watt power amp provide more total SPL than a single 50 Watt speaker driven at the same power level ??
I know SPL is all about how much air can you move, or so I think.
Can anybody speak to the physics or the physicality of this ??
Edify me, please...
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Kevin Raymer
Zum / Knaggs / Breedlove
Fractal Audio |
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Les Cargill
From:
Oklahoma City, Ok, USA
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Posted 13 Oct 2014 2:49 pm
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For speakers of the same "sensitivity", no. You'd still be sinking 25 each to the two 25 watters.
It may be that the 25 watt speakers put out more sound for one watt than the 50 does. Then yes - you
have a higher limit.
Two speakers may also have cancellations close up that are not there with one. |
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Dave Grafe
From:
Hudson River Valley NY
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Posted 13 Oct 2014 5:53 pm
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| Quote: |
Will two 25 watt speakers driven by a 50 watt power amp provide more total SPL than a single 50 Watt speaker driven at the same power level ??
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It's been addressed here before, but in a nutshell, it mostly depends on the amplifier and the speaker wiring scheme.
A solid state amp driving 2 identical speakers IN PARALLEL will deliver twice the electrical power as it would to a single such speaker, so in this scheme the answer is yes, the pair would be more, but not twice, the SPL as the single speaker.
A transformer-coupled amp, such as virtually all tube-driven amps, is wired for optimum efficiency at a given load impedance, and adding speakers will not necessarily increase the output power or SPL. Impedance mis-matches with such amps are to be undertaken advisedly.
| Quote: |
I know SPL is all about how much air can you move, or so I think. |
Sort of kind of...SPL per watt is about sensitivity, one JBL K120 will deliver twice the SPL per watt available from many OEM speakers. |
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Steve Collins
From:
Alaska, USA
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Les Cargill
From:
Oklahoma City, Ok, USA
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Posted 14 Oct 2014 2:41 pm
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| Dave Grafe wrote: |
A solid state amp driving 2 identical speakers IN PARALLEL
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My bad - never wire speakers in series unless you have adult supervision. I ASSumed...
| Quote: |
will deliver twice the electrical power as it would to a single such speaker, so in this scheme the answer is yes, the pair would be more, but not twice, the SPL as the single speaker.
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Beggin' pardon guv'nor ( tugs forelock in obesiance )...
In the case he described, we have 1) two 25 watt speakers vs. 2) one 50 watt speaker. If they're all three the same sensitivity, then they put out the same level at 50 watts for 1) or 2) - assuming all the impedences work out ( each 25 is an 8 ohm and each 50 is 4 ohm, they are in parallel... )
One 25W speaker would not be run at 50W (for long ) and would be -3dB to what the other two configurations put out @25W.
In reality, it's never that simple.
| Quote: |
A transformer-coupled amp, such as virtually all tube-driven amps, is wired for optimum efficiency at a given load impedance, and adding speakers will not necessarily increase the output power or SPL. Impedance mis-matches with such amps are to be undertaken advisedly.
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Indeed! For tube amps, get a pro with inside knowledge of that amp to bless any alternate speaker configurations other than the one it came with. |
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Donny Hinson
From:
Glen Burnie, Md. U.S.A.
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Posted 14 Oct 2014 3:52 pm
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| Quote: |
| Will two 25 watt speakers driven by a 50 watt power amp provide more total SPL than a single 50 Watt speaker driven at the same power level ?? |
As the "speaker wattage" is a usless number, the question really doesn't have much validity. Really, the basics are simply that more speakers move more air, and therefore sound louder (other things being equal, which they seldom are).
But....
Electrical watts and audio watts are two different
things. Fifty watts of electrical power fed into an "efficient" speaker might yeild from two to five watts of actual audio output power, depending on the efficiency of the speaker. Remember: the wattage rating of a speaker has little or nothing to do with it's efficiency, and how much audio output it actually yeilds with a given input. Manufacturer's listed SPL's can be equally useless, because they can be measured at different frequencies, but are usually given for only one specific frequency. If the testing methods and equipment aren't identical, comparisons of any statistics generated are pretty meaningless.
This stuff is so complex and involved that I resolve to judge by using only one factor: "How does it sound?" 
Numbers, unless they're on a paycheck or a timeslip, just don't impress me very much. |
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